CPT code 40818: Oral graft harvest, vestibular mucosa2026 Medicare rate & RVUs in California
Reports harvesting oral mucosa from the mouth vestibule for use as a graft during reconstructive surgery, such as urethral reconstruction.
Medicare pays $385.56–$484.27 for 40818 in the office in California, from Chico, CA to San Benito County, CA. Which amount applies depends on the service address.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
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On this page 9 sections
What 40818 covers
This service removes oral mucosa from the vestibule of the mouth to provide donor tissue for reconstruction at another site. It is performed by a surgeon, often an oral and maxillofacial surgeon, otolaryngologist, or urologist, when a reconstructive procedure calls for oral mucosal graft tissue. A familiar clinical use is harvesting buccal mucosa for urethral reconstruction. The code represents the donor-site harvest, not removal of a mouth lesion or the reconstruction at the recipient site.
Report the harvest when the operative note identifies the oral donor site, the tissue obtained, and its graft purpose; report the recipient-site procedure separately when performed and supported. CMS assigns a 90-day global period, including the day-before preoperative visit and 90 days of related postoperative care. When multiple procedures occur in the same session, the highest-valued procedure is paid in full and other procedures are subject to the standard 50% multiple-procedure reduction. Modifier 50 is inappropriate for this code. Assistant-at-surgery payment requires documented medical necessity; co-surgeon and team-surgery billing are not permitted.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
Where 40818 pays more and less in California
The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.
29 payment localities
$385.56 to $484.27
29 of 29 payment localities
| Payment locality | Office | Facility |
|---|---|---|
| Bakersfield, CA | $386.60 | $257.37 |
| Chico, CA | $385.56 | $256.33 |
| El Centro, CA | $385.62 | $256.39 |
| Fresno, CA | $385.56 | $256.33 |
| Hanford, CA | $385.56 | $256.33 |
| Los Angeles, CA | $411.93 | $272.45 |
| Madera, CA | $385.56 | $256.33 |
| Marin County, CA | $473.65 | $307.41 |
| Merced, CA | $385.56 | $256.33 |
| Modesto, CA | $385.56 | $256.33 |
| Napa, CA | $447.31 | $291.91 |
| Oxnard, CA | $409.99 | $270.63 |
| Redding, CA | $385.56 | $256.33 |
| Rest of California | $385.56 | $256.33 |
| Riverside, CA | $389.36 | $260.13 |
| Sacramento, CA | $404.76 | $267.64 |
| Salinas, CA | $403.26 | $266.61 |
| San Benito County, CA | $484.27 | $314.25 |
| San Diego, CA | $412.88 | $271.86 |
| San Francisco, CA | $473.26 | $307.01 |
| San Luis Obispo, CA | $396.76 | $262.47 |
| Santa Clara County, CA | $482.65 | $312.63 |
| Santa Cruz, CA | $416.93 | $273.67 |
| Santa Maria, CA | $404.81 | $267.33 |
| Santa Rosa, CA | $421.15 | $276.36 |
| Stockton, CA | $385.56 | $256.33 |
| Vallejo, CA | $446.73 | $291.34 |
| Visalia, CA | $385.56 | $256.33 |
| Yuba City, CA | $385.56 | $256.33 |
How the 40818 rate is calculated
Each of 40818’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 40818
RVUs × geographic indexes × conversion factor
Work2.76
2.76 RVUs× 1.000 GPCI
Practice expense7.80
7.80 RVUs× 1.000 GPCI
Malpractice0.35
0.35 RVUs× 1.000 GPCI
Adjusted RVUs
10.9100
Conversion factor
$33.4009
Medicare rate
$364.40
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 40818
40818 has a 90-day global period: related visits in that window are included in the surgery payment.
CMS payment indicators · 40818
Oral graft harvest, vestibular mucosa
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 090 | Major surgery: the day before, the day of, and 90 days after are included. |
| Multiple procedures | 2 | Standard reduction: highest-valued procedure at 100%, others at 50%. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 0 | Not paid without supporting documentation. |
| Co-surgeons (62) | 0 | Not permitted. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
| Split (54/55/56) | 0.09/0.81/0.10 | Share of the payment for pre-op, the procedure itself, and post-op care. |
Global surgery period · 40818
Oral graft harvest, vestibular mucosa
90-day global period ends
Dec 30, 2026
Covers Sep 30, 2026 through Dec 30, 2026 (92 days, including the day before surgery).
Visit on Oct 31, 2026
Day 30 of the 90-day post-op period: related follow-up care is included in the surgical payment.
Pre-op dayGlobal period
What modifiers do to the payment
Modifier 51 · payment effect
With and without the modifier
40818 without 51 · national office
$364.40
Oral graft harvest, vestibular mucosa
40818-51 · Second procedure: 50%
$182.20
When this isn’t the highest-valued procedure in the session, Medicare pays 50% of its fee schedule amount (the highest is paid at 100%).
40818 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 40808Mouth biopsyOral vestibule
- 40808 reports biopsy of a mouth lesion. Use 40818 when the oral mucosa is harvested to serve as donor graft tissue.
- 40810Mouth lesion excisionWithout repair
- 40810 is for excising a mouth lesion, not obtaining tissue for grafting. The operative purpose distinguishes the services.
- 40812Oral lesion excisionSimple repair
- 40812 addresses lesion excision with repair; 40818 describes harvesting oral mucosa for use as a graft at another site.
40818 billing questions
How is graft harvest different from excising a mouth lesion?
This code is for taking oral mucosa as donor tissue for grafting. Lesion-excision codes apply when the purpose is removal of a lesion, with code selection based on the service performed.
Can the recipient-site reconstruction be reported separately?
Yes, when a distinct recipient-site procedure is performed and documented. For example, oral mucosa may be harvested for a urethral reconstruction, with the reconstruction reported under its applicable code.
Does modifier 50 apply when mucosa is harvested from both sides?
No. CMS identifies bilateral adjustment as inappropriate for this code, so modifier 50 should not be used.
What postoperative care is included?
The 90-day global period includes the day-before preoperative visit and 90 days of related postoperative care.
When is an assistant at surgery payable?
Assistant-at-surgery payment requires documentation of medical necessity. Co-surgeon and team-surgery billing are not permitted for this code.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file lines behind this rate
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